1. Field of the Invention
The invention relates to a system for the collection and retransfusion of autologous blood.
2. Description of the Prior Art
In a known system of this type, namely the "solcotransystem," the collecting vessel for the drainage blood consists of a bag arranged inside a rigid plastic bottle which can be evacuated to produce a negative pressure in the bag and to maintain this negative pressure for a certain period of time. A given amount of an anticoagulant is placed in the bag before the blood is introduced. When the bag is filled to the desired level, it is separated from the tube leading from it to the drain, so that its contents can be retransfused to the patient through a microfilter.
One disadvantage of this conventional system is that, depending on the wound conditions, a varying degree of hemolysis can arise, which leads to substantial fluctuations in the quality of the erythrocytes to be retransfused. An additional disadvantage is that the blood is subjected to a relatively long contact with a foreign surface before it can be mixed with the anticoagulant fluid in the collecting bottle. This leads to an activation of clotting factors as well as the kinin and complement systems. The activation of the Ca-dependent clotting factors is not interrupted until the blood comes into contact with the anticoagulant fluid stabilizer. Adequate mixing of the blood with the anticoagulant is only assured if the two fluids are repeatedly mechanically mixed, which is a further disadvantage of the known system. Aside from activated clotting factors, the blood contained in the collecting vessel also contains fat and fatty tissue from the area of the wound. Although the blood is mechanically filtered by the microfilter prior to transfusion, small clots, less than 40 .mu.l in size, of fat and activated clotting factors nevertheless can enter the circulatory system of the patient, so that the risk of thromboembolic complications and fat embolisms cannot be precluded, which is extremely disadvantageous.
Another known system is free of this last disadvantage. In this conventional system the blood is subjected to a washing process using a physiological common salt solution to remove the fat and clotting factors. However, this system is very expensive and personnel-intensive in operation, which is why it is only employed in large clinics. In addition, both of these known systems are open, so that the risk of contamination exists.